I do not smoke marijuana but my wife does. I have to take a hair follicle test. Will I fail because the weed is in the hair, even though I do not smoke?

Yes, quite possible. Best to wash your hair a lot, but why do you have to take a test ?

Tickle is absolutely correct. External contamination is a major problem in hair drug testing involving any smoked product. The chemical washes used prior to testing are ineffective in many cases. See In Vitro Contamination of Hair by Marijuana Smoke, 2004 (https://www.askmehelpdesk.com/addictions/hair-folical-test-630445.html) Several follow-up tests have added additional weight to this finding.